Originally Posted by
Kaleredar
As others have pointed out, him checking the round and therefore interfering with the way it was prepared may have been seen as compromising the way a prop master set it up, therefore requiring the prop master to re-load the gun because it had been potentially compromised by the actor. To which you would then say that the actor should then check it again, requiring the prop master to check it again, requiring the actor to check it again, and... on into infinity?
And regardless, it's really not expected that any person that's going to hold a firearm in a film has to go through some sort of training to know live rounds from blank rounds. Do you expect people playing pilots sitting in green screened cockpits to go through pilot training "just in case" the grounded aircraft they're in takes off?